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No. 619,014. Patented Feb. '7, I899.

I T. E. DRUHAN.

ELECTRIC ARC LAMP. (Application filed. Dec. 1, 1898.) (No Model.)

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UNITED STATES PATENT CFFICE.

THOMAS E. DROI-IAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS 82;

HALSKE ELECTRIC COMPANY OF AMERICA, OF SAME PLACE.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 619,014, dated February7, 1899. v Application filed December 1,1898. Serial No- 697,9'74. (Nomodel.)

To all whom it may concern:

Be it known that I, THOMAS E. DROHAN, a citizen of the United States,residing at Ohicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Electric-Arc Lamps,(Case I No. 189,) of which the following is a full, clear,

concise, and exact description.

My invention relates to electric-arc lamps; and its object is to'provideimproved means for cutting a lamp out of circuit during the time inwhich the trimmer is engaged in supplying the same with fresh carbons.

In accordance with my invention the lowercarbon holder is mounted in amanner to permit of its being let down or otherwise moved away from itsnormal position to afford easy access to the working parts of the lamp,and switching mechanism is associated with the said lower-carbonsupport, whereby the circuit of the lamp is automatically broken whenthe said lower-carbon support is moved away from its normal position.For instance, the side rod of the lamp which supports the lowercarbonholder may be constructed in two parts or members, one of which maybefastened rigidly to the lamp-frame, but carefully insulated from anycurrent-carrying part thereof, and the other part of the side rod may bearranged to slide up and down upon the stationary part or member. Themovable part of the side rod is the one which immediately supports thelower-carbon holder, and at the upper end of the said movable part onemember of a switch may be mounted, which is adapted when thelower-carbon holder is in its normal position to engage with acomplemental switch member stationarily mounted upon the lamp-frame. Thestationary 1nember of the switch may be connected with acurrent-carrying part of the lamp, so that When the lower-carbon holderis in its normal position current will be supplied through thestationary member of the switch, and thence, by way of the movablemember thereof associated with the movable member of the side rod, tothe lower-carbon holder and carbon. It will be understood that when thelower-carbon holder is let down to enable the drawings, in which trimmerto insert new carbons in the lamp this very act will cause the twomembers of the switch aforesaid to be separated, thus breaking thecircuit and disconnecting the lower-carbon holder from anycurrent-carrying portion of the lamp.

By making use of my invention a number of arc-lamps may be provided uponone circuit, and any of the lamps may be trimmed without the necessityof cutting out all the remaining lamps of that circuit at the mainswitch. Further, the lamp-trimmer is protected from accidental burnswhile trimming a lamp, even though the continuity of the lamp-circuit isnot broken save by the act of letting down the lower carbon, as aboveexplained.

My invention will be described more particularly by reference to theaccompanying Figure l is an elevation of an arc-lamp embodying myinvention, some of the parts being broken away and others indicateddiagrammatically for clearness. Fig. 2 is a detail elevation of the siderod and lower-car- Similar letters of reference are used to desighatethe same parts wherever they are shown.

The regulating mechanism of the arc-lamp is of a well-known type, andconsists, essentially, in a solenoid a, having a hollow softiron core,through which the upper carbon 1) is fed. The clutching mechanism foreffecting. the feeding of the upper carbon as it is burned away forms nopart of this invention and need not be described.

The upper carbon 1) is electrically connected with one end of thewinding of the solenoid Ct, the other end of said winding beingconnected with the source of current-supply, such as one of the mains ofa system of electrical distribution. The lower carbon 0 may theconductor 6, however, is made by way of the separable switch members f fThe member f may consist of a blade portion mounted stationarily uponapart ofthe framework a, and the other switch member may consist of aspring clip or socket mounted upon the upper end of the movable member(1 of the side rod. Fig. 1 shows the two members of the switch inengagement with one another, so that the lower carbon 0 will thus beelectrically connected with the main 6.

The member 01 of the side rod is constructed to slide up and down uponthe other member (1 in thefollowing manner: At the upper end of themovable member (1 a collar 01 is rigidly fastened, which is adapted toslide freely to and fro along the stationary member d Likewise near thebottom of the member (1 a similar collar 61 is provided, rigidly securedthereto, but freely movable to and fro along 1 the member d. When themovable member is in its normal position, as illustrated in Fig. 1, theparts may be so maintained by a setscrew 9, mounted upon the movablemember cl, passing therethrough and engaging with a recess d providedfor that purpose in the lower end of the stationary member (1 When thelower-carbon holder has been let down, as illustrated in Fig.2, thecollar d will engage with the collar d and prevent further relativemovement-that is, will prevent the movable member from falling oifentirely.

By reference to Fig. 2, it will be seen that the two members f and f ofthe switch are automatically separated by the very act of letting downthe lower-carbon holder. This of course will break the circuit of thelamp, and thus the possibility of the trimmer becoming burned byaccidental contact with a current conducting part will be avoided. \Vhenthe burned carbons have been removed and fresh ones inserted in placethereof, the trimmer raises the lowercarbon holder into its normalposition, thereby causing the two members f f of the switchautomatically to engage with one another and establish the circuit ofthe lamp. He may then secure the parts in position by tightening theset-screw g.

It will be understood that 'my invention is applicable to electric-arclamps of widelyditfering characters, and the construction of theswitching mechanism may be varied to a great extent without departingfrom the spirit of my invention. I do not wish, therefore, to beunderstood as limiting myself to the precise construction shown; but,

Having thus described my invention, I claim as new, and desire to secureby Letters Patent, together with such modifications as may be made bythe exercise of mere mechanical skill and only with those limitationsexpressed or by law implied in view of the state of the related arts,the following 1. Inan electric-arc lamp, the combination with a pair ofrelatively-movable carbons and means for regulating and feeding thesame, of a movable support for one of said carbons; means for movingsaid support away from its normal position to permit the lamp to .betrimmed, and switching mechanism associated with said movablecarbon-support and 0perated by the movement thereof, said switchingmechanism controlling the continuity of the lamp-circuit, whereby thecircuit of the lamp will automatically be broken when the saidcarbon-support is moved away from its normal position, and completedwhen said carbon-support is replaced in its normal po sition,substantially as described.

2. The combination with a carbon-holder of an arc-lamp,of amountingtherefor permitting the same to be moved away from its normalposition to permit the lamp to be trimmed; switching mechanismcontrolling the continuity of the lamp-circuit, and a connection betweensaid carbon-holder and switching mechanism, whereby the latter isautomatically actuated by the movement of said carbonholder,substantially as described.

3. The combination with the lower-carbon holder of an arc-lamp, of amovable support therefor permitting the same to be let down tofacilitate the trimming of the lamp; a mov-' able switch member operatedby said movable support; a complemental switch member associated withthe lamp-frame and connected or adapted to be connected with a source ofcurrent, said movable switch member being disengaged from itscomplemental member when the lower-carbon holder is let down; and anelectrical connection between said switch member and the lower-carbonholder, sub stantially as and for the purpose set forth.

4. The combination with the lower-carbon holder of an arc-lamp, of aside rod support ing said lower-carbon holder, said side rod beingformed of two members movable rela tively to one another, whereby thelower carbon may be let down to facilitate the trimming of the lamp,said lower-carbon holder being electrically connected with said siderod, an electrical connection normally existing between the side rod anda current-car rying part of the lamp, whereby current is supplied to thelower carbon, and means associated with the side rod for automaticallybreaking the last-mentioned electrical connection by the relativemovement of the two parts of said side rod, substantially as described.

5. The combination with the lower-carbon holder of an arc-lamp, of aside rod supporting the same, said side rod having two membersrelatively movable longitudinallyof one another, whereby saidlower-carbon holder may be let down to facilitate the trimming of thelamp; a stationary switch member connected or adapted to be connectedwith a current-carrying portion of the lamp, and a complemental switchmember normally engaging therewith and electrically connected with theIn Witness whereof I hereunto subscribe my name this 25th day ofNovember, A. D. 1898.

THOMAS E. DROI'IAN.

Witnesses:

DE WITT O. TANNER, A. L. LAWRENCE.

